Method of refining petroleum oil distillates



Dec. 4, 1934. J, D. FIELDS 1,983,220

METHOD OF REFINING PETROLEUM OIL DISTILLATES Filed March 18, 1935HIIIIIIIIIIIHHII Patented Dec. 4, 1934 PATENT OFFICE METHOD F BEFININGPETROLEUM OIL DISTILLATES John D. Fields, Los Angeles, Calif.

Application March 18,

9 Claims.

My invention relates to a method of refining distillates and moreparticularly pertains to a process for treating petroleum distillates toremove certain impurities therefrom in which a catalytic action of analkali metal is employed in a manner similar to and for the purposes setforth in United States Letters Patent Number 1,864,719, issued to me`under date of June 28, 1932, for Method of refining distillates.

An object of the invention is to provide a method of the above characterwhereby the purification of distillates to effect the production of asweet smelling, water white, stable product of great brilliancy. may beobtained by removing undesirable substances or compounds contained inthe distillate which impart to it objectionable odors and discoloration,and which render it unstable, through the medium of an alkali metalcatalyst, in which the treatment of the distillates may be effected in aclosed tank with either a continuous or intermittent operation, withoutthe use ofmechanical agitators, pumps or like instrumentalities, andwhereby the purifying treatment may beeffected at atmospherictemperatures and pressures and in such manner as to accomplish therefining and purification of the distillates at greatly'` reduced costover processes now generally in use. i Another object is to provide amethod of purifying distillates with the aid of alkali metal catalyzersin which the impurities will separate from the liquid under treatment ina tank in such man1,

ner that the impurities may be readilyyremoved from the rened product,and inwhich the impurities are rendered of such characterastohave;

commercialvalue. l

Another object is to provide a process of the above character in whichthe purification action may be rapidlyeected and without appreciableloss of light gasoline vapors and withoutloss of the octane number 'orother aromatics and thus avoid raising the boiling point of theresultant gasoline. A

Another object is. to provide a distillate refining method in which thedistillates are acted on by an alkali metal. catalyzer in such `manner,as

to effect coagulation and precipitation of gums in the liquid undertreatment, and in which dissolving of such coagulatedv substances heldinsuspensicn in 'the'llquidl together with the gums that havebeenjprecipitated on the alkali metal catalyzers will .be effected toform a heavy oil which may be readily drawn on lfrom the liquid undertreatment. f V Another object is to provide a processwhich is 1933,Serial No. 661,471

(Cl. ISIS- 23) applicable for use in the purifying of pressuredistillates either before or subsequent to treatment by theusual acidprocess, or independent thereof, and which where employed subsequent tothe acid treatment the use of sodium plumbite will be obviated. i

A further object is to provide a distillate refining process employingan alkali metal catalyst in which the amount of consumption of alkalimetal required for treatment of a particular quality of distillate maybe accurately predetermined.

'I'he invention and the mode of accomplishing the objects and advantagesabove set forth, together with such other objects and advantages as maysubsequently appear, further resides in the steps and featureshereinafter more fully described and claimed and illustrated by way ofexample in the accompanying drawing in which the figure is adiagrammatic view of a distillate refining apparatus and depicting themanner of carrying the invention into effect.

The apparatus as shown in the drawing ernbodies a tank 2 for containingthe distillates during treatment and which tank for the purpose offacilitating a substantially uniform action throughout the liquid bodytherein is formed with adownwardly converging or conical shaped bottomportion 3 from the lower end of which leads a discharge pipe 4 fittedwith a cut-off valve 5.

The upper end of the tank 2 is provided with an opening 6 fitted with acover 7 and which opening iisfprovided forfthe purpose of giving accessto fthe interior of the tank'auditorleriablingfithe*inf` sertion intothe tank yan'dfrernoval"tl'ierefrciin-of` .atcagevdzcarrying-catalyticbodies 9 which bodies mare'formed of solid alkali metal such as sodium,potassium, or lithium. The cage 8 may be of any suitable construction,being here shown as formed of wire netting but manifestly may be of anysuitable open formation to permit circulation of liquid therethrough.One end of the cage is fitted with a removable cover 10. A rack 12 isprovided at a suitable point within the tank for affording a support forthe cage 8. I

In some instances cage 8 may be dispensed with and the alkali metalbodies placed loose in the tank 2.

The distillates to be treated are delivered to the tank from anysuitable source of supply through a conduit 14 fitted with a valve 15which conduit leads into the upper portion of the tank. As a means forconveying gases from the tank so as to prevent development of excessivepressures therein, the upper end of the tank is fitted with a vent pipe16 equipped with a cut-oi! valve 17.

An important feature of the present invention resides in delivering tothe distillate content of the tank a halogen salt in solution, and forthis purpose a reservoris provided for such solution, as indicated at18, from which leads a conduit 19 communicating with the upper end ofthe tank through a regulating valve 20. The reservoir 18 is tted with asuitable measuring gage 21 to enable drawing off of a predeterminedvolume of the solution from the reservoir 18.

The tank 2 is equipped with a gage glass 22 for indicating the level ofthe distillates within the tank, and is also iltted with a gage glass 23for indicating the level of a heavy oil embodying separated impuritieswhich accumulate in the lower portion of the tank.

While the present method is applicable to the treatment of petroleumdistillates of various fractions or combinations thereof, it isespecially applicable to the treatment of distillates of low boilingpoint, that is distillates which pass off at temperatures up toapproximately 500 degrees Fahrenheit, and may be distillates derivedfrom heavy petroleum oils by cracking. In fact the method is designed tobe employed in the treatment of any hydrocarbons containing impuritieswhich are subject to being removed as herein set forth by the action ofalkali metal catalyzers.

As an example of impurities that are subject to being removed by thisprocess are those of resinous and gummy character and include the olenhydrocarbons embracing mono-oleilns, the di-olefins or poly-olens, andthe acetylene isomers of di-olefins; naphthenes; sulfur compounds;nitrogen bases and acid compounds.

Without binding myself toany particular theory of operation it seemsproper to state that the impurities removed or to be removed are suchthat cold solid alkali metal may act as a catalyst to produce acondensing reaction to form products which are soluble in a menstruumembodying halogen salts, these products being usually oi a gummy orresinous or rubbery nature which coagulate, and which undoubtedlyinclude certain sulfur compounds and which when present in distillatesimpart an objectionable odor and discoloration thereto and which renderthe distillates unstable and also result in the formation of gums orresinous deposits on utilizing the refined product as in combusting itin motors.

The alkali metal catalyst is employed in the form of solid bodies whichare so shaped that they may be arranged within the cage 8 in a manner toafford interstices through which the distillates may ow and in suchmanner as to cause the flowing distillates to be deected into numeroussmall streams between adjacent catalytic bodies, and whereby thedistillates will be brought into superficial contact with or in closeproximity to a considerable area of the surface o1' the catalyticbodies. For this purpose the catalyzers may be shaped'in the form ofspheres, blocks or bars. They are placed within the cage 8 through theopening in the upper end thereof, and the cage is placed within the tankthrough the opening 6 as before described. The catalyzer bodies arepreferably thus confined in a cage to prevent their floating to the topof the liquid under treatment and also to facilitate the removal andreplacement of the catalyzers as occasion requires.

The halogen salt solution, which as before stated includes solutions ofmagnesium chloride, ferrous chloride, zinc chloride, and hydrousaluminum chloride, is prepared in the yproportion of approxlmatehr onegram of the halogen salt to one liter of water, but w h proportion issubject to variations, the propo ons being such that the solution willact as a solvent in cleaning the (resinous and other gummy) impuritiesfrom the alkali metal and also to dissolve the coagulated substancesheld in suspension in the distillates. In other words, the solution maycomprise approximately one part in 100 of halogen salts to 99 parts ofwater by weight, thus forming a one per cent solution, but a stronger orweaker solution may be used. I

The halogen salt solution may be employed in the proportion ofapproximately 10 c. c. of the solution to four liters of thedistillates, which is equivalent to approximately 10 gallons of solutionto one hundred barrels of distillate, but the proportions may be variedsince an excess of salt solution is not detrimental.

In carrying the method into effect a quantity of the alkalimetalcatalyzers is placed within the tank, as in the cage 8; whichquantity is proportioned to the volume o`f distillates to be treated,and according to the proportions of impurities contained in thedistillates to be treated, for example if tests show that thedistillates to be treated carry approximately 250 millograms of gum per100 c. c. of distillates. then approximately two and one-half ounces ofalkali metal will be employed for each forty-two gallon barrel ofdistillates to be treated. In other words, assuming the tank to be of100 barrel capacity, then the quantity of alkali metal used will beapproximately 250. ounces. It will be understood, however, that theproportions may be varied as occasion requires. Manifestly an excess ofthe alkali metal in proportion to the volume of distillate undertreatment will not be detrimental.

A predetermined volume of distillates to be treated is then delivered tothe tank and coniined therein; the valves 5 and 15 then being closed. Aprecipitation of heavy gums immediately commences due to the catalyticaction of the alkali metal; which eects condensation of such impuritiesinto a flocculent form. The ilocculent impurities whose coagulation hasthus been effected by the action of the catalyzers collect in part onthe catalyzer bodies, and a portion of such impurities are suspended inthe distillates. This action of the alkali metal is immediate and onsuch action having occurred a measured volume of the halogen saltsolution in the proportion above stated is delivered to the tank, as byopening the valve 20, which solution on flowing into the distillateswithin the tank sinks therein and comes in contact with the alkali metalthereby immediately effecting the evolution of hydrogen gas and thuscausing violent agitation of the liquid in the tank.

This agitation serves to cause all of the liquid in the tank to bebrought into intimate contact or close association with the alkali metaland thereby causing the latter to effect formation of the ilocculated orcoagulated impurities throughout the liquid under treatment and alsocausing the salt solution to act on such impurities as are held insuspension in the distillates and also deposited on the alkali metalcatalyzers; the salt solution acting as a solvent to convert thecoagulated substances (resins and gums) into a heavy reddish oil whichsettles to the bottom of the tank from whence the oil may be drawn offas by opening the valve 5 from time to time as occasion may require oron completion of the treatment of the acid process.

Lacasse d The process above described is carried out at normalatmospheric temperatures or at the ordinary temperatures of the liquiddistillates, and does not require the generation and application ofextraneous heat. The process is also carried on at normal atmosphericpressures; the evolved gases which may accumulate in the tank andthereby create pressures therein being drawn oil as occasion requiresthrough the vent pipe 16.

By this process no mechanical agitation of the liquid is necessary sincethe agitation set up from the formation of hydrogen gas eiects therequisite contact of the distillates with the alkali metal and also theintermixture of the salt solution and the distillates, within a shortperiod. It has been found in practice that approximately 10 minutes isrequired to eiect treatment of a batch of distillates in the mannerabove set forth where the proper proportions of distillate, alkali metaland salt solution are employed.

The resultant red oil which contains the removeddmpurities in solutionconstitutes a saturated solution of sodium hydroxide which is readilyseparable from the distillates and is a product of commercial value.

The resultant distillates will be practically free of objectionable gumand sulfur compounds and is t for use for commercial purposes, and ifredistilled the majority of distillates will be water white and will bestable when exposed to sun light.

However there are instanceswhere because of the nature and quantity ofresinous, gummy and sulfur compound impurities contained in somedistillates, it is found desirable to employ the present process inconjunction with the sulfuric acid process either preliminary orsubsequent thereto, in which instance it is found that a much lesserquantity of sulfuric acid is required for carrying out the. acidtreatment than where such acid treatment is employed alone, and alsothat it is unnecessary to employ the usual doctor treatment with sodiumplumbite as ordinarily used in to be employed together with the acidprocess the distillates are treated with a solution of one to three lbs.of Baume sulfuric acid per barrel of distillates under treatment. Asbefore stated this acid treatment may be effected either before or aftertreatment by the present process.

The process is highly economical since it has been found in vpracticethat in the treatment of a cracked or pressure distillate containingapbarrel.

While I have shown and described a particular apparatus for carrying theinvention into effect, various other structures may be employed. In

i fact the invention may be practiced by means of the ordinarydistillate storage tanks, and without the provision of any specialequipment. Furthermore while the mode of operation has been described asintermittent, that is to say, as applied to the treatment of a batch ofdistillates in a tank which after being treated is drawn from the tankand the latter recharged, it is manifest that the method may be carriedout by a continuous operation, as by maintaining a ilow of distillatesand salt solution in proper proportions over a mass of alkali metalcatalyzers.

I claim:

1. The method of removing impurities from petroleum distillates,consisting in subjecting a Where the present process is relatively largevolume of such' distillates in liquid condition to the catalytic actionof a relatively small mass of solid bodies of an alkali metal in thecold, for a sufficient period of time to effect coagulation of the bulkof the impurities, whereby some of the impurities become precipi tatedon the alkali metal and some is held in suspension in the distillates ina ilocculent state, then adding to the distillates a relatively smallquantity of a solution of halogen salts whereby the coagulatedimpurities will be dissolved and converted into a heavy oil andseparating said oil from the distillates.

2. The methodV of removing from petroleum distillates impuritiescontained in solution therein. consisting in maintaining a relativelysmall mass of solid bodies of alkali metal and a relatively'large volumeof the distillates in intimate juxtaposition while at about normalatmospheric temperature, for such length of time as to effeetcoagulation of at least a major portion of the impurities in thedistillates treated, then adding to the distillates a small volume of asolution of mineral salts capable of dissolving the coagulatedimpurities and to convert same into a heavy oil and separating said oilfrom the distillates.

3. A process which comprises placing a relatively small mass of solidalkali metal within a large bulk of petroleum oil distillates, to causecoagulation of certain substances in said distillates, introducing intothe distillates and into contact with said alkali metals a small volumeof a solution of halogen salts to eiect evolution of hydrogen gas andresultant agitation of the distillates and to cause said solution todissolve the coagulates into a heavy oil, and separating said oil fromthe distillates.

4. A process which comprises placing a relatively small mass of solidalkali metal within a relatively large bulk of petroleum oil distillatesand maintaining said metal within thedistillates until coagulation ofsubstances in the distillates takes place, then contacting the alkalimetal while in the distillates with a small volume of a halogen saltsolution to effect evolution of hydrogen gas, and supplying such volumeof said salt solution to the distillates as to eilect conversion of thecoagulates into oil, and removing the oil and formed gases.

5. A process which comprises placing a relatively small mass of solidalkali metal within a relatively large bulk of petroleum oil distillatesand maintaining said metal within the distillates until coagulation ofsubstances in the distillates takes place, then contacting the alkalimetal while in the distillates with a small volume of a halogen saltsolution lto eifect evolution of hydrogen gas, and supplying such volumeof said salt solution to the distillates as to effect conversion of thecoagulates into oil, removing the oil and formed gases, subjecting theremaining distillates to the action cf sulfuric acid, and nally washingand redistilling the distillate product.

6. The process of refining petroleum oil distillates which consists inplacing Within a relatively large bulk of distillates a relatively smallmass of solid alkali metal. adding to the distillates a small volume ofa halogen salt solution of about one per cent strength in such manner asto bring said solution and alkali metal into contact, employing saidsolution in such proportions as to effect diolution of at least aportion of said alkali metal and to effect dissolving of coagulatesformed in the distlllates by the catalytic action of the alkali metal.

7. In a process for rening petroleum oil distillates, the step whichconsists in adding a small volume of a solution of halogen salts to alarge bulk of distillates containing a relatively small amount of solidalkali metal.

8. The process of refining petroleum oil distillates to effect removalof resinous and gummy constituents thereof consisting in subjecting thedistillates to the combined action of a solid alkali metal and asolution of halogen salts :in substantially the proportions of tengallons of the salt solution and two hundred and fifty ounces of alkalimetal to one hundred barrels of distillates.

peratures and pressures.

. JOHN D. FIELDS.

